Waterpumps, BB VS SB

Just a couple of easy questions. As I understand it, waterpumps are a drag (resistance) on the engine, as they are run via the crank/pulley/belts, and electric water-pumps decrease that drag, thus providing a little more HP, and seems to be a bit lighter also. While both the power and weight differance is very small, every bit counts <img src='/_siteconfigs/_global/images/community/bbcode/grin.gif'> . So why are there so few cars that use electric water-pumps <img src='/_siteconfigs/_global/images/community/bbcode/confused.gif'> ! <img src='/_siteconfigs/_global/images/community/bbcode/confused.gif'> ? Are there any known real reasons for this, such as they are not reliable, cost too much <img src='/_siteconfigs/_global/images/community/bbcode/frown.gif'> , etc?
The other question is, all other things being equal, ie- same air/fuel induction, exhaust, parts,etc., is there a differance between a Big-Block 427 and a Small-Block 427, other than the actual size/weight differance, such as the BB provides more Tq, or the SB makes more HP <img src='/_siteconfigs/_global/images/community/bbcode/confused.gif'> ?
I am just wondering, I have not heard or read much on the pros and cons of each of these questions ( on same cid blocks. I have read and heard LOTS about cid and block size differance), and I have always wondered about it. Thanks for any and all info <img src='/_siteconfigs/_global/images/community/bbcode/laugh.gif'> [bold]![/bold]  

Well your first question on water pumps not being electic, BB or SB, is heat not only generated by engine heat,but most important is the heat generated by the electric motor running the pump. Now where do you think this heat going to go? answer: in the cooling system right? yes, but when the engine gets hot the water pump gets hotter and it does not even out it ramps in a linear fasion and could eventually burn up the pump and the your screwd.
Thats why smart gear heads(like myself) rid themselves of that antique cluch fan and install ELECTIC FANS on the radiator. On my 79 vette I installed a High volume water pump with a dual electric fan mounted rigth on the radiater, no more stupid shrouds and my Vette has NEVER run cooler.
My Vette runs a 355 and with a solid Scant forged Balanced enternal assembly with 10.5 comp. 218-224 deg @50 w/ 488 IN @ 488 EX stock heads mill. .025 flat and ported to Smokey Yunks 72 Indy design w/ ss valves comp pro roler rockers @1:6 push with a Holley 750 dubble pumper. I scare the Hell out of some BB's all day long.